Patent GB-406311-A (GB)
Title: Improvements in or relating to gramophones and similar sound reproducing apparatus
IPC: G11B3/085
Filed: 1932-08-19
Abstract: 406,311. Gramophones. LEWIN, D. G., 16, Boundary Road, Hawkenbury, Tunbridge Wells. Aug. 19, 1932, No. 23303. [Class 40 (ii).] A gramophone is mounted within a casing which is entirely closed except for a slot in alignment with the turntable, and is so constructed that when a record is inserted through the slot it is automatically placed on the turntable, played, and then returned through the slot. Fig. 1 is a plan of the mechanism viewed from above, and Fig. 2 is a plan viewed from below the motor-board. When a record is fed into the slot 3, Fig. 1, it passes between two rollers 5, 6 mounted on interconnected pivoted arms 7, 8, and forces them apart to an extent depending on the size of the record. The record also engages a pin 20 on an arm 21 which is pivoted about the axis of the roller 5, and by rocking this arm it operates, through a slotted link 22, a latch 23, releasing a lever 25, Fig. 2. One end of this lever carries a rod 27, which, when the lever 25 is freed, rises under the action of a spring, and rocks both the lever 25 and a lever 30 pivoted in a hollow arm 32, which is pivotally mounted on a sleeve 29 on the motorboard, Figs. 1 and 4. A plunger 33 at an end of the lever 30 is moved down as the rod 27 rises, engaging the surface of the record. When the latter has been thrust sufficiently inwards, the central hole therein allows the plunger 33 to move lower downwards, so that the rod 27 rises further and swings the lever 25 further to a point where a contact 35 thereon, Fig. 2, closes the circuit of a motor 37. The motor is connected through a clutch to a sprocket 39, which is geared to a cam drum 38. This drum rotates through 180‹ before being automatically stopped, as subsequently described. During this rotation, a rod 46 connected to the underside of the drum, rotates the hollow arm 32, by means of an arm 47 on the sleeve 29. Thus, by the engagement of the plunger 33 with the hole therein, the record is carried to the centre of the turntable. At the same time, by means of a link 48 the arm 47 rotates a bell-crank 49, which carries a stop 50 coacting with an arm 51 on a vertical spindle 52. The pick-up arm 53, Figs. 1 and 11, is pivoted at 75 on the spindle 52, which is fixed in a sleeve 74, and this assemblage is capable of limited vertical movement, the pick-up being normally clear of the record. As the member 49 is rotated, it allows the arm 51 to turn under the indirect action of a spring 54, the spring being connected to another arm 56 which is temporarily secured by a catch to the arm 51. The pick-up arm is by this means swung inwardly until the pick-up is over the plain margin of the record. The permissible extent of inward movement of the pick-up arm is determined by a stop 15, controlled by the movement of the rollers 5, 6 when the record is forced between them. With a 10-inch record the stop 15 is not moved forward from the position shown in Fig. 2 sufficiently to limit the movement of the arm 56, but the insertion of a 12-inch record causes the stop to take up a position where it is in the path of a set-screw 58 on the arm 56, so that the pick-up is stopped at the appropriate greater distance from the centre of the record. When the initial rocking movement of the lever 25 occurs, a pin 59 thereon pases into an horizontal groove in the edge of the cam drum 38. After the drum has rotated through 180‹, the pin 59 is depressed by an inclined wall at the end of the cam groove. This movement rocks the lever 25 still further, causing the plunger 33 on the lever 30 to enter an aperture in the turntable and to press down a plunger 64 in the upper end of the turntable spindle 66, Fig. 15. The turntable 4 is normally loose on the spindle, which is driven by the motor, but depression of the plunger 64 clutches the spindle to the turntable, which thereupon starts to rotate. At the same time, the movement of the lever 25 causes a lever 71 to effect the lowering of the pick-up on to the record, by the connection of the lever 71 with the sleeve 74. Disengagement of the catch connecting the arms 51, 56 occurs, and a spring 81 gently urges the needle into the commencement of the record groove. As soon as the pickup has been lowered, the drive from the motor to the cam drum 38 is disconnected. This is effected by operating a clutch 86, Fig. 15, normally connecting the spindle 66 to the sprocket 39, the clutch being shifted by means of levers 84, 83, under the control of a cam 82 rotating with the drum 38. The record is then played, and at the end of the playing, the mechanism for repositioning the pick-up arm and removing the record is automatically restarted by the effect produced when the needle enters a quick run-off or eccentric groove on the record. For this purpose there is provided a device of known type comprising a lever 96, Fig. 1, slowly moved by the pick-up arm, and carrying a stiffly-pivoted member 99 coacting with a projection 102 rotating with the turntable. When the member 99 is suddenly advanced at the end of playing of the record, the projection 102 turns it about its pivot, causing it to engage a pin 104 projecting up from a finger 90 pivoted at the end of the lever 83. The finger 90, which was serving to hold the clutch 86 out of action, is thereby moved aside, allowing the clutch to engage again, so that the cam drum 38 and the cam 82 are restarted. The drum 38 then begins to make a second half-revolution, and allows the lever 25 to turn sufficiently to raise the plunger 33, so that the turntable is declutched. Simultaneously, by the movements of the levers 71, 47, and 48, the pick-up arm is raised and swung outwardly, and the arm 32 is swung so that the record is carried back to the slot 3 in the cabinet. The cam 82 resets the lever 83, and finally the pin 59 on the lever 25 passes upwardly through the end of the cam slot in the drum 38, so that the lever 25 is permitted to break the motor circuit and to disengage the plunger 33 from the record. The finger 90 may be moved manually, by means of mechanism 105, 106, adapted to act on the pin 104 and operated by a push-button 95, Fig. 1, so that the pick-up and record manipulating mechanism can be restarted at any time whilst a record is being played.